The main objectives of this project are to demonstrate and investigate by means of a computer summation technique the responses evoked at the surface of the scalp of normal humans by discrete electrical stimuli delivered to the pulp of individual teeth as a method of eliciting "acute experimental pain". Normative data will be established as regards form, latency, amplitude and topographic distribution of these potentials. Attempts will be made to correlate objective intensities of electrical stimulus, subjectively assessed pain intensities, cerebral evoked response parameters and MMPI measures of proneness to somatic distress (T scores, scale l). Tooth pulp-evoked cerebral responses will be compared with those elicited by electrical stimulation of the median nerve at the wrist. The effects of local anesthesia, administration of selected analgesic drugs and related agents on tooth-pulp-evoked cerebral responses will be correlated with the alteration of subjective reported pain induced by these medications.